THEORY OF MULTI PHOTON EXCITATION

有机分子中电子跃迁的理论计算 不同激发模式的分子使人们能够预测 多光子激发的截面和基本各向异性。 对于双光子，nadh的基本各向异性接近0.54。 激发波长在690-740 nm，比0.37的值高出46% 观察到的是单光子激发。这种观察到的更高的 双光子激发的各向异性与INDO/SDCI一致 单、双光子跃迁的计算。NADH显示一个 低的双光子激发截面，这表明 对于双光子荧光，NADH的荧光可以忽略不计。 显微镜下观察，不会显著干扰观察 用于标记细胞的其他外在探针的TPIF。

Theoretical calculations of electronic transitions in organic molecules for different modes of excitation allow one to predict the cross-section and fundamental anisotropy for multi-photon excitation. The fundamental anisotropy of NADH is near 0.54 for two-photon excitation from 690-740 nm, which is 46% higher than the value of 0.37 observed for one-photon excitation. This observation of a higher anisotropy with two-photon excitation was consistent with INDO/SDCI calculation of the one- and two-photon transition. NADH displays a low cross-section for two photon excitation, which suggest that fluorescence from NADH will be negligible for two-photon fluorescence microscopy and will not significantly interfere with observations of TPIF of other extrinsic probes used to label cells.